Photoshop Blend Modes for Unity3D

So here’s a small thing that may help some folks out. Ages ago, while researching how Photoshop blend modes work behind the scenes, I stumbled across this fantastic demo on Shadertoy and have kept it bookmarked since. Recently, I wanted to do some overlay blending in Unity, so went back to the Shadertoy example and did a quick port to the .cginc file below:

PhotoshopBlendModes.cginc

C#

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#ifndef PHOTOSHOP_BLENDMODES_INCLUDED

#define PHOTOSHOP_BLENDMODES_INCLUDED

//

// Ported from https://www.shadertoy.com/view/XdS3RW

//

// Original License:

//

// Creative Commons CC0 1.0 Universal (CC-0)

//

// 25 of the layer blending modes from Photoshop.

//

// The ones I couldn't figure out are from Nvidia's advanced blend equations extension spec -

Usage should be fairly self explanatory, but here’s a quick Overlay shader example:

Overlay.shader

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Shader"Blendmodes/Overlay"

{

Properties

{

_MainTex("Texture",2D)="white"{}

_BlendTex("Blend Texture",2D)="white"{}

}

SubShader

{

Tags{"RenderType"="Opaque"}

LOD100

Pass

{

CGPROGRAM

#pragma vertex vert

#pragma fragment frag

#include "UnityCG.cginc"

#include "Assets/Path/To/PhotoshopBlendModes.cginc"

structappdata

{

float4 vertex:POSITION;

float2 uv:TEXCOORD0;

};

structv2f

{

float2 uv:TEXCOORD0;

float4 vertex:SV_POSITION;

};

sampler2D _BlendTex;

sampler2D _MainTex;

float4 _MainTex_ST;

v2f vert(appdatav)

{

v2fo;

o.vertex=UnityObjectToClipPos(v.vertex);

o.uv=TRANSFORM_TEX(v.uv,_MainTex);

returno;

}

fixed4 frag(v2fi):SV_Target

{

fixed4 mainColor=tex2D(_MainTex,i.uv);

fixed4 blendColor=tex2D(_BlendTex,i.uv);

// perform blend

mainColor.xyz=Overlay(mainColor.xyz,blendColor.xyz);

returnmainColor;

}

ENDCG

}

}

}

Using these two images (which I just happened to find in my Dropbox directory so I’m claiming ownership) can produce all the effects in the picture at the top of this page (left-to-right top-to-bottom: Add, ColorBurn, ColorDodge, DarkerColor, Difference, Divide, Exclusion, HardLight, HardMix, Lighten, LighterColor, LinearBurn, LinearDodge, LinearLight, Overlay, PinLight, Screen, SoftLight, Subtract, and VividLight).

I left off the blends Hue, Color, Saturation, and Luminosity simply because they were a little more expensive and I wasn’t interested at the time. Feel free to add them back in – easy enough to do.

Enjoy.

Edit:

Just for the sake of completion, I’ve added the Hue, Color, Saturation, and Luminosity blend modes. Keep in mind, to simplify usage of these, you may only need to add a _Color property to your shader rather than a _BlendTex like in the example above.